Light emitting diode package having heat dissipating slugs

ABSTRACT

A light emitting diode package having heat dissipating slugs is provided. The light emitting diode package comprises first and second heat dissipating slugs formed of a conductive material and spaced apart from each other; a package main body coupled to the first and second heat dissipating slugs to support the first and second heat dissipating slugs; and a light emitting diode die electrically connected to the first and second heat dissipating slugs, wherein the respective first and second heat dissipating slugs are exposed to the outside through lower and side surfaces of the package main body. As such, the first and second heat dissipating slugs can be used as external leads.

CROSS REFERENCE RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/204,619, filed on Sep. 4, 2008, and claims priority from and thebenefit of Korean Patent Application No. 10-2007-0089351, filed on Sep.4, 2007, which are both hereby incorporated by reference for allpurposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light emitting diode package, andmore particularly, to a light emitting diode package having heatdissipating slugs.

2. Discussion of the Background

Recently, a gallium nitride based light emitting diode (LED) die havebeen increasingly used as a light source. The optical power of such alight emitting diode is generally proportional to a magnitude of aninput current. Accordingly, if the magnitude of the input currentsupplied to the light emitting diode is increased, high optical powercan be obtained. However, the increase in the magnitude of the inputcurrent causes the junction temperature of the light emitting diode toincrease. The increase in the junction temperature of the light emittingdiode causes a photometric efficiency to be reduced, wherein thephotometric efficiency indicates what portion of an input energy isconverted into visible light. Accordingly, it is required to prevent theincrease in the junction temperature of the light emitting diode due tothe increase in the magnitude of the input current.

Conventionally, in order to prevent junction temperature of a lightemitting diode from being increased, a package has been used in which aheat sink is coupled to a lead frame to thereby dissipate heat throughthe heat sink. However, since the package is manufactured by coupling aseparate heat sink to the lead frame, there is a problem in that astructure of the package and therefore a process of manufacturing thesame may be complicated, and thus, the manufacturing cost of the packagemay be increased.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a light emitting diodepackage having an improved heat dissipation performance.

Another object of the present invention is to provide a light emittingdiode package having a simple structure as well as easily dissipatingheat generated from a light emitting diode die.

According to the present invention for achieving the objects, there isprovided a light emitting diode package having heat dissipating slugs.The light emitting diode package comprises first and second heatdissipating slugs spaced apart from each other. The first and secondheat dissipating slugs are formed of a conductive material. A packagemain body is coupled to the first and second heat dissipating slugs tosupport the first and second heat dissipating slugs. Further, a lightemitting diode die is electrically connected to the first and secondheat dissipating slugs. In the meantime, the respective first and secondheat dissipating slugs are exposed to the outside through lower and sidesurfaces of the package main body. As such, the first and second heatdissipating slugs can be used as external leads, so that the lightemitting package with a simple structure can be provided. Further, sinceheat can be dissipated through the first and second heat dissipatingslugs, whereby the heat dissipation performance can be improved.

Further, portions of the first and second heat dissipating slugs whichare exposed through the side surfaces of the package main body mayinclude a plurality of fins. The fins cause the surface area of thefirst and second heat dissipating slugs to be increased, so that theheat dissipation performance can be improved.

According to some embodiments of the present invention, the package mainbody may have a cavity for exposing upper surfaces of the first andsecond heat dissipating slugs. The light emitting diode die may bemounted on the upper surface of the first heat dissipating slug exposedthrough the cavity. In addition, a bonding wire can electrically connectthe light emitting diode die to the second heat dissipating slug.

Meanwhile, the package main body may be formed of transparent resin. Insuch a case, the package main body can cover the light emitting diodedie and/or the bonding wire.

According to some embodiments of the present invention, the first heatdissipating slug may have a cavity functioning as a reflective surface.The light emitting diode die is mounted in the cavity of the first heatdissipating slug.

According to another embodiment of the present invention, a metalreflector may be positioned on the first and second heat dissipatingslugs, wherein the light emitting diode die may be mounted inside of themetal reflector. Accordingly, heat can be discharged through the metalreflector, whereby the heat dissipation performance can be furtherimproved. The package main body can be attached to the metal reflectorto support the metal reflector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a light emitting diode packagehaving heat dissipating slugs according to an embodiment of the presentinvention.

FIG. 2 is a sectional view taken along line A-A of FIG. 1.

FIG. 3 is a sectional view illustrating a light emitting diode packagehaving heat dissipating slugs according to another embodiment of thepresent invention.

FIG. 4 is a sectional view illustrating a light emitting diode packagehaving heat dissipating slugs according to a further embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a light emitting diode packagehaving heat dissipating slugs according to an embodiment of the presentinvention, and FIG. 2 is a sectional view taken along line A-A of FIG.1.

Referring to FIGS. 1 and 2, the light emitting diode package accordingto this embodiment includes first and second heat dissipating slugs 21and 23, a package main body 25 and a light emitting diode die 27.

The first and second heat dissipating slugs 21 and 23 are spaced apartfrom each other, thereby being electrically insulated from each other.The first and second heat dissipating slugs 21 and 23 may be formed of aconductive material, e.g., a pure metal such as copper, silver, nickel,aluminum and molybdenum, a metal alloy thereof, or a complex materialthereof. Such heat dissipating slugs are also thermally conductive andhave relatively large volumes, so that heat generated from the lightemitting diode die 27 can be easily dissipated.

Meanwhile, the package main body 25 is coupled to the first and secondheat dissipating slugs 21 and 23, thereby supporting them. The packagemain body 25 may be formed of a plastic or ceramic material and definesthe whole shape of the light emitting diode package. Each of the firstand second heat dissipating slugs 21 and 23 is exposed to the outsidethrough lower and side surfaces of the package main body 25. At thistime, portions of the first and second heat dissipating slugs 21 and 23,which are exposed through the side surfaces of the package main body 25,may be provided with a plurality of fins 21 a and 23 a, respectively.The fins 21 a and 23 a cause a surface area of the first and second heatdissipating slugs 21 and 23 to be increased and thus help the heatdissipating slugs to be cooled, thereby improving the heat dissipationefficiency of the light emitting diode package.

In the meantime, the light emitting diode die 27 is electricallyconnected to the first and second heat dissipating slugs 21 and 23. Forexample, the light emitting diode die 27 may be electrically connectedto the first heat dissipating slug 21 through a conductive adhesive (notshown) and electrically connected to the second heat dissipating slug 23through a bonding wire 29. Alternatively, the light emitting diode die27 may be mounted on the first heat dissipating slug 21 through anadhesive and electrically connected to the first and second heatdissipating slugs 21 and 23 through bonding wires, respectively.

Meanwhile, the package main body 25 may be formed of transparent resin.In such a case, the package main body 25 may cover the light emittingdiode die 27 and the bonding wire 29. The transparent resin may containa phosphor for converting a wavelength of light emitted from the lightemitting diode die 27. Alternatively, if the package main body 25 isformed of opaque plastic or ceramic, the package main body 25 has acavity for exposing upper surfaces of the first and second heatdissipating slugs 21 and 23 to the outside. At this time, the lightemitting diode die 27 may be mounted on the upper surface of the firstheat dissipating slug 21, which is exposed through the cavity andelectrically connected to the second heat dissipating slug 23 throughthe bonding wire 29. Further, the cavity may be filled with transparentresin (not shown), which may contain a phosphor.

An inner wall 31 of the cavity is configured to be slanted therebyfunctioning as a reflective surface for reflecting the light emittedfrom the light emitting diode die 27. Further, the inner wall 31 may becoated with a reflective material in order to increase the opticalreflectivity.

FIG. 3 is a sectional view illustrating a light emitting diode packagehaving heat dissipating slugs according to another embodiment of thepresent invention.

Referring to FIG. 3, the light emitting diode package according to thisembodiment has the substantially same configuration as the lightemitting diode package illustrated with reference to FIGS. 1 and 2, butis different in that a first heat dissipating slug 21 shown in FIG. 3has a cavity which forms a reflective surface 51. The light emittingdiode die 27 is mounted in the cavity. Meanwhile, as illustrated withreference to FIGS. 1 and 2, a package main body 55 may be formed ofplastic or ceramic. If the package main body 55 is formed of opaqueplastic or ceramic, the package main body 55 has a cavity for exposingthe cavity of the first heat dissipating slug 21.

Generally, if the light emitted from the light emitting diode die 27 isdirectly incident on a plastic material, the light may cause the plasticto be deteriorated, e.g., structurally deformed or discolored.Accordingly, if the package main body 55 is formed of a plasticmaterial, the light may cause the package main body 55 to bedeteriorated, so that the reflectivity of the inner wall 31 of thecavity (see FIG. 2) may be reduced. However, according to thisembodiment, the first heat dissipating slug 21 is formed with thereflective surface, so that the package main body 55 can be preventedfrom being deteriorated due to the light emitted from the light emittingdiode die 27. Further, the first heat dissipating slug 21 is formed of ametal with high reflectivity, so that the light emitting efficiency ofthe light emitting diode package can be improved.

FIG. 4 is a sectional view illustrating a light emitting diode packagehaving heat dissipating slugs according to a further embodiment of thepresent invention.

Referring to FIG. 4, the light emitting diode package according to thisembodiment has the substantially same structure as the light emittingdiode package illustrated with reference to FIGS. 1 and 2, but isdifferent in that the light emitting diode package shown in FIG. 4further includes a metal reflector 71. The light emitting diode die 27is mounted in the metal reflector 71. Accordingly, the light emittedfrom the light emitting diode die 27 is reflected from an inner surfaceof the metal reflector 71 and then exits to the outside.

The metal reflector 71 may be formed of the same material as the firstand second heat dissipating slugs 21 and 23, but the present inventionis not limited thereto. For example, the metal reflector 71 may beformed of a variety of metal materials with high reflectivity, such assilver, aluminum, nickel or the like.

Meanwhile, a package main body 75 may be not only coupled to the firstand second heat dissipating slugs 21 and 23 to support them but alsoattached to the metal reflector 71 to support it. Further, the metalreflector 71 may be attached to the first and second heat dissipatingslugs 21 and 23.

According to this embodiment, the employment of the metal reflector 71prevents the package main body 75 from being deteriorated and increasesthe reflectivity of the light emitted from the light emitting diode die27. Further, heat can be discharged to the outside through the metalreflector 71, so that the heat dissipation performance can be improved.

According to the embodiments of the present invention, the heatdissipating slugs can be used as external leads, so that the lightemitting package with a simple structure can be provided. Further, sincethe first and second heat dissipating slugs are exposed to the outsidethrough both side surfaces of the package main body and the lowersurface thereof, whereby the heat dissipation performance of the lightemitting diode package can be improved.

1. A light emitting diode device, comprising: a light emitting diode; aheat dissipating part comprising a plurality of fins and a wallsurrounding at least a part of the light emitting diode; and a plasticmaterial part coupled to the wall of the heat dissipating part, whereinthe plurality of fins are exposed outside of the light emitting diodedevice.
 2. The light emitting diode device of claim 1, wherein theplastic material part comprises a transparent material.
 3. The lightemitting diode device of claim 2, wherein the transparent materialcomprises a phosphor.
 4. The light emitting diode device of claim 3,wherein the transparent material comprising a phosphor is spaced apartfrom the light emitting diode.
 5. The light emitting diode device ofclaim 1, wherein the plastic material part is spaced apart from thelight emitting diode.
 6. The light emitting diode device of claim 1,wherein a surface of the wall is uncovered by the plastic material part.7. The light emitting diode device of claim 1, wherein the wallcomprises a reflecting material.
 8. The light emitting diode device ofclaim 7, wherein the reflecting material is at least one of silver,aluminum, or nickel.
 9. The light emitting diode device of claim 7,wherein a surface of the plastic material part is coplanar with asurface of the heat dissipating part.
 10. The light emitting diodedevice of claim 9, wherein the surface of the heat dissipating part,coplanar with the surface of the plastic material part, comprises an endsurface of the wall.
 11. A light emitting diode device, comprising: alight emitting diode; a conducive material part comprising a heatdissipating slug formed of a conductive material, the heat dissipatingslug comprising a plurality of fins and a wall surrounding at least partof the light emitting diode; and a plastic material part coupled to thewall of the heat dissipating slug.
 12. The light emitting diode deviceof claim 11, wherein the plastic material part comprises a transparentmaterial.
 13. The light emitting diode device of claim 12, wherein thetransparent material comprises a phosphor.
 14. The light emitting diodedevice of claim 13, wherein the transparent material comprising thephosphor is spaced apart from the light emitting diode.
 15. The lightemitting diode device of claim 11, wherein the plastic material part isspaced apart from the light emitting diode.
 16. The light emitting diodedevice of claim 11, wherein an end surface of the wall is uncovered bythe plastic material part.
 17. The light emitting diode device of claim16, wherein the end surface is coplanar with a surface of the plasticmaterial part.